Can a saved person live an unsuccessful, depressed life?

You mean like a man acquainted with sorrows?

I think we can. To be saved we only need to have faith in Jesus, repent of our sins and take them to Him for forgiveness. It does not require that we live a life that shines, that follows all God’s ways. We can live our married life and think of our own well-being ahead of our mate’s well-being as scripture tells us to do. We can be a gossip instead of making friends of others and still go to God for forgiveness. We do not need to think in a positive way as Phil. 4:8 tells us to be saved, but we need to follow it to be successful and let our light shine.

In fact, there are unsaved persons who do not know Jesus but follow His suggestions for triumphant living who are then happy, content and successful in this life but dead in the life to come. There are saved persons who have no light that shines.

The person who shines brightest is the person who listens well to all the guidance of Christ and lets what is of Christ shine through them. They are both a saved person and a person who lets Christ shine through them.

Yes. I believe Christians can lead "unsuccessful" and depressed lives. Being both depressed and being unsuccessful can actually be related, as one can cause the other.

On success, there are multiple takes on what success means. Many Christians have no ambition to be successful under the "worldly" definition, in terms of education, wealth, etc. since they believe that being saved is enough and nothing else really matters. Even though JWs are not technically Christian, they come to mind. Many JWs did not pursue higher education because they thought the world was going to end soon (they previously had apocalypse predictions, now sure about now). They were at one point one of the lowest educated and poor populations.

Yes, I believe Christians can be depressed. I personally don't know people who have perfect mental health. There are many causes for depression, such as medication side effects, grief from loss of lived one, etc. Hopefully, the depression will go away after some time rather than be a lifelong issue. Yet, some forms of depression are a lifelong issue and are diagnosed medical conditions. I think there are a variety of reasons why a person could be depressed.

Let me consult with the book of Jeremiah....BRB

Look at Job.. he lost everything, right into the pits of despair. Through that experience he might have got some serious health problems. I'm the end he had restoration from God to what he lost, but he may have had long lasting issues after ward.

Success.. spiritually is very different to the worlds